1. Field of the Invention
This invention relates to progressive die sensors utilized to indicate an unaligned condition of a workpiece strip being stamped during a progressive stamping operation.
2. Description of the Prior Art
Progressive dies are used in manufacturing to perform stamping operations on a continuous workpiece strip. A number of work stations are arranged along a path through which the strip is continuously fed. Punches and cooperable female die sections are mounted at the various work stations so that vertical stamping movement of an upper punch holder causes deformation of the workpiece. Usually, the punches are mounted on an upper punch holder which is moved vertically with respect to a lower shoe that mounts the female sections.
At the first station of a progressive die stamping operation, a guide hole is pierced in the workpiece strip such that a probe located at a subsequent station can sense whether there is a properly aligned condition between the work stations and the workpiece strip. Vertical stamping movement of the upper punch holder has also been terminated by the alignment sensing probe when an unaligned workpiece condition is detected. However, this termination of the stamping operation has required the design, fabrication and assembly for each job of a sensor for detecting when the probe moves in response to an unaligned workpiece condition. Such design and assembly, of course, results in considerable labor and consequent expense.